The objective of this program is to gain increased understanding of the neural mechanisms which underlie hearing through an integrated series of studies: 1) Study of the function and structure of the cochlear nuclear complex by means of intracellular recording and labeling of neurons in vivo; 2) analysis of the ways in which speech sounds as encoded in discharges of auditory nerve fibers as revealed by microelectrode recordings; 3) development of a computer simulation model of the peripheral auditory system, including the micromechanical vibrations of the organ of Corti and the electromechanical and transmitter - release characteristics of the hair cells; 4) microelectrode studies of binaural interaction in neurons of the superior olive complex and inferior colliculus with the aim of understanding the function of these structures in sound localization. All these projects dependent on a computer-based laboratory system which control auditory stimuli, analyse temporal discharges of single and multi-unit recordings and in mathematical modeling. Another objective involves the study of the phylogenetically old piriform cortex with the goal of developing a rigorous model for the integrative processes of this system and there by providing general principles applicable to other cortical areas. A major element of this program is the three dimensional reconstruction of anatomical material. Reconstructions of HRP labeled material or EM material can be rotated and resectioned in any plane.